With reference to FIG. 1, a human pelvis is shown and generally indicated by reference numeral 10. The human pelvis 10 is comprised of a right and a left hemi-pelvis respectively indicated by reference numerals 12 and 14. The right and left hemi-pelvis 12 and 14 may also be referred to as a right and left hip bone 12 and 14, respectively. Mature hip bones 12 and 14 are each comprised of three principle bones fused together: An ilium 16, an ischium 18 and a pubis 20. The ilium 16 is the upper and the largest part of the pelvis and articulates on its inner aspect with a sacrum 22 at a sacroiliac joint 24. The ischium 18 is the more distal and posterior of the three principal bones of the pelvis 10 and may be commonly referred as a seat bone or a huckle bone. The pubis 20 is the more medial and anterior of the three principal bones of the pelvis 10 and may be commonly referred to as a share bone or a pubic bone.
The ilium 16, the ischium 18, and the pubis 20 are separated from each other by cartilage in young subjects (not shown) but are fused together as solid bone in a mature adult. The union of the ilium 16, the ischium 18, and the pubis 20 takes place, among other places, in and around a large cup-shaped articular cavity known as the acetabulum generally indicated by reference numeral 26. The acetabulum 26 is a hollow, cuplike portion of the hip bone 12 into which a head 28 of a femur 30 fits. The bone and muscle structure surrounding the head 28 of the femur 30 and the acetabulum 26 of the hip bone 12 allows for among other things the ability to walk. It will be appreciated that there are muscles and associated connective tissue that retain the head 28 of the femur 30 within the acetabulum 26 and also provide for flexing and motion of the femur 30 relative to the hip bone 12. It will also be appreciated that while reference is made to either the hip bone 12, the discussion hitherto and throughout is applicable to hip bone 14.
The sacrum 22 is a triangular-shaped bone lying between the fifth lumbar vertebra (partially shown) and the coccyx (partially shown), which can be commonly referred to as the tailbone. The sacrum 22 consists of five vertebrae fused together and it articulates on each side with the respective ilia 16 to form sacroiliac joints 24. The sacrum 22, as well of as the other bones of the pelvis 10, may become damaged due to injury, or various medical conditions such as cancer, osteoporosis or various medical trauma, and as such may have to be partially removed and/or replaced in whole.
With reference to FIG. 2, the various medical conditions as mentioned above may deprive a patient of the acetabulum 26 of the hip bone 12 thereby necessitating a prosthetic to be implanted in its place. It will be appreciated that damage to the hip bone 12 can range from loss of use of one of the acetabulums 26 all the way to complete loss of one or both of the hip bones 12 and 14. If presented with a complete loss of one of the hip bone 12, it will be appreciated that a prosthetic hip bone or hemi-pelvis must be constructed to not only connect to the head 28 of the femur 30 but also connect to the opposing pubis bone 20a and the sacrum 22. If the hip bone 12 is not a complete loss it will be appreciated that the hip bone replacement must connect to the remaining portions of the hip bone 12 to otherwise restore complete functionality to the pelvis 10.
Hip prosthetics require bone screws and/or bone fusing material to establish a suitable connection to the remaining and healthy portions of the hip bone. Hip prosthetics also require bolts or bone screws threaded through brackets to connect to the remaining healthy bone. The additional hardware adds cost and complexity. The brackets further require that a larger area of the remaining healthy bone be exposed.